For an electrically powered vehicle such as an electric vehicle and a hybrid vehicle driving a traction motor by power received from a power storage device represented by a rechargeable battery, a configuration for charging an in-vehicle power storage device by a power supply external to the vehicle (hereinafter also simply referred to as an “external power supply”) has been proposed. Charging a power storage device by an external power supply will hereinafter also be simply referred to as “external charging” or the like.
Generally an electrically powered vehicle has mounted therein two types of power storage devices, i.e., a high-voltage power storage device (a main battery, for example) used to feed power to a traction motor and a low-voltage power storage device (an auxiliary battery, for example) used to feed power to auxiliaries including a control device.
Japanese Patent Laying-Open No. 2009-225587 (PTD 1) describes a configuration to provide external charging more efficiently and also ensure an auxiliary load system's operation. Specifically, the publication describes providing a path to charge a main battery 10 externally to allow the external charging and the auxiliary load system's operation to be both established while a relay 150C (a system main relay) between a traction motor 30 and main battery 10 is turned off.
Furthermore, Japanese Patent Laying-Open Nos. 9-009417 and 9-065509 (PTDs 2 and 3, respectively) describe techniques for miniaturizing a charger mounted in an electric vehicle. Specifically, a main battery and a battery for auxiliaries share a charger to achieve a miniaturized and more inexpensive charger.